1. Field of the Invention
The invention generally relates to an optical module and an assembling method thereof and, in particular, to a lens module and an assembling method thereof.
2. Description of Related Art
A lens module is a key component in a camera. The optical quality of a picture shot by the camera is mainly determined by the optical properties of the lens module and an image sensor, for example, a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) sensor.
In the recent years, the camera is integrated into a portable electronic device such as a mobile phone, a smart phone, or a tablet computer. As a result, the size of the lens module is reduced to comply with the requirement for a small size of the portable electronic device.
In a conventional camera in the portable electronic device, there is a single lens in the lens module or are a plurality of lenses arranged on the optical axis of the lens module. That is, the lens module is circularly symmetric. Consequently, the lens module may be fixed on a substrate, on which an image sensor disposed, by screwing. However, in another conventional camera, a lens array is used in the lens module to achieve refocus or stereoscopic imaging. If the lens module containing the lens array is screwed to the substrate to a certain appropriate focusing position, the orientation relationship between the lens module and the image sensor will be not correct since the lens module is not circularly symmetric and is rotated with respect to the image sensor when screwing.